MUTAGENICITY AND PAH:S OF PARTICULATE EMISSIONS OF TWO-STROKE CHAINSAW ENGINES

Particulate emissions of a two-stroke chainsaw engine were collected under controlled conditions in a test bench using a dilution tunnel for sampling. Two different types of gasolines and lubricating oils and the effect of exhaust after-treatment catalyst were studied. Particulate bound PAH:s and mutagenicity of the collected samples were determined.

The particulates were found to originate mainly from the lubricating oil. There was a good correlation between the particulate bound PAH:s and the mutagenicity of the soluble organic fraction of the particulates. The amount of SOF was > 95% and originated mainly from lubricating oil. The catalyst performed more effectively with totally non-aromatic gasoline and synthetic lubricating oil than with reformulated gasoline with aromatics < 35 vol-% and mineral oil based lubricating oil. Using MTBE as an oxygenate in non-aromatic, special small engine gasoline reduced the PAH emissions and mutagenicity significantly even without the catalyst and the catalyst reduced the emissions even further.